Why does my .7 solve error result in bad track?
The problem is displayed in your screenshot.



First off the iPhone 4 has a 3.85mm focal length (part of the iPhone 4 preset), no were near 457.

Because you had a focal length that was way off, it messed up blender big time. No doubt you had Refine in the Solve settings set to adjust the K1 and K2 values. -1237926.25 is a HUGE number, way bigger then anything you will ever really need; for that matter the K1 value is way too high. The focal length and Lens Distortion values are the cause of your problem.